Image forming apparatus and image forming method

• US 6,894,808 B1
• Filed: 08/18/2000
• Issued: 05/17/2005
• Est. Priority Date: 08/19/1999
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Kawakami, Haruko, Hamamura, Naoko
• Primary Examiner(s): Wallerson, Mark
• Assistant Examiner(s): BURLESON, MICHAEL L
• Application Number:
  US09/641,337
• Time in Patent Office: 1,733 Days
• Field of Search: 358/1.9, 358/537, 358/538, 358/1.2, 358/451, 358/452
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/393 Enlarging or reducing
• CPC Class Codes: H04N 1/40062 Discrimination between different image types, e.g. two-tone, continuous tone
• CPC Class Codes: H04N 1/6072 adapting to different types of images, e.g. characters, graphs, black and white image portions

Abstract

An input section performs a color conversion process, etc. for image data from a color scanner section. A discrimination section generates a discrimination signal representative of “character”, “non-character”, etc. on the basis of an image signal from the input section. A first processing section performs a filtering process, etc. for the image signal from the input section, and switches the method of such a process on the basis of the discrimination signal from the discrimination section. An enlargement/reduction section enlarges or reduces the discrimination signal from the discrimination section and the image signal from the first processing section. A second processing section subjects the enlarged/reduced image signal form the enlargement/reduction section to a black-added printing process, a gamma conversion process, etc., and switches the method of such a process on the basis of the enlarged/reduced discrimination signal from the enlargement/reduction section.

Claims

1. An image processing apparatus for subjecting an input image signal to an enlargement/reduction process on the basis of a predetermined enlargement/reduction magnification, the apparatus comprising:

first discrimination means for generating a first discrimination signal by determining an attribute of each of pixels on the basis of the input image signal;

image enlargement/reduction means for subjecting the input image signal to the enlargement/reduction process on the basis of the enlargement/reduction magnification;

second discrimination means for generating a second discrimination signal by subjecting the first discrimination signal from the first discrimination means to the enlargement/reduction process on the basis of the enlargement/reduction magnification; and

image processing means for performing an image process for the enlarged/reduced image signal from the image enlargement/reduction means on the basis of the second discrimination signal.

2. An image processing apparatus according to claim 1, wherein the first discrimination signal generated by the first discrimination means is a two-value signal.

3. An image processing apparatus according to claim 1, wherein the first discrimination signal generated by the first discrimination means is a multi-value signal.

4. An image processing apparatus according to claim 1, wherein an image signal selected by the first discrimination signal from the first discrimination means from among image signals processed and output from a plurality of image processing units, which have mutually different characteristics for applying a predetermined image process to the input image signal, is subjected by said image enlargement/reduction means to the enlargement/reduction process on the basis of the enlargement/reduction magnification.

5. An image processing apparatus according to claim 1, wherein said second discrimination means comprises:

pixel division means for dividing pixel information associated with the first discrimination signal, which pixel information belongs to an object pixel range, on the basis of the enlargement/reduction magnification, and retaining the divided pixel information;

a plurality of arithmetic operation means for subjecting the pixel information belonging to the object pixel range, which has been divided by the pixel division means, to predetermined arithmetic operations, thereby outputting enlarged/reduced discrimination signals associated with the pixels; and

selection means for selecting one of the output signals from the plural arithmetic operation means on the basis of an externally provided switching condition.

6. An image processing apparatus according to claim 5, wherein the externally provided switching condition, which is input to the selection means, is one of an enlargement/reduction magnification, a kind of an original, and an image process adjustment value, which are selected by external input operations.

7. An image processing apparatus according to claim 5, wherein where the first discrimination signal generated by the first discrimination means is a two-value signal, each of the plural arithmetic operation means performs an arithmetic operation of one of a logical sum of pixel information in an object range divided by the pixel division means, a logical product of the pixel information in the object range divided by the pixel division means, a pixel value at a fixed position such as a first pixel or a last pixel in the object range, and a weighted sum corresponding to the magnification.

8. An image processing apparatus according to claim 5, wherein where the first discrimination signal generated by the first discrimination means is a multi-value signal, each of the plural arithmetic operation means performs an arithmetic operation of one of a pixel value at a fixed position, such as a first pixel or a last pixel, of pixel information in an object range divided by the pixel division means, a maximum or minimum value of the pixel information in the object range, and a weighted sum corresponding to the magnification.

9. An image processing method for subjecting an input image signal to an enlargement/reduction process on the basis of a predetermined enlargement/reduction magnification, the method comprising the steps of:

generating a first discrimination signal by determining an attribute of each of pixels on the basis of the input image signal;

subjecting the input image signal to the enlargement/reduction process on the basis of the enlargement/reduction magnification;

generating a second discrimination signal by subjecting the first discrimination signal from the first discrimination means to the enlargement/reduction process on the basis of the enlargement/reduction magnification; and

performing an image process for the enlarged/reduced image signal from the image enlargement/reduction means on the basis of the second discrimination signal.